Electron discharge device



May l0, 1932. F. K. RICHTMYER 1,857,608

ELECTRoN DISCHARGE DEVICE Filed July 29, 1924 ATTORNEY Patented .May1.0, 14l321`v i ,UNTED STATES,

FLOYD KARKER limnnimzrm, ori-ITHACA, NEW Yoan- *Y ELECTRON DISCHARGEDEVICE Application med July 29,

i This invention `relates to an electron discharge device and moreparticularly, to a device ofv the evacuated or gas-lledtype designed forthe detection or amplification ofl electrical energy.

In the construction of radio tubes or other electron discharge devices,it is desirable .to obtain the maximum mutual conductance, with a givenamplification constant, to-reduce the plate resistanceorfspace currentefect to a minimum and toprovide as large Y an electron-emitting surfacefor the cathode as is possible. The plate resistance may be decreased bydecreasing theaverage distance from the anodefto the cathode. `This maybe accomplished by using a cylindrical anode or plate mountedconcentrically' with zrespect to the cathode and relatively closethereto; The electron-emitting surface of the cathode may be increasedby increasing thelength of the cathode. However, because of inherentstructural limitations in tubesvof thistypeT the cathode or filamentcannot exceed a cer-` tain length. Thisdiiticulty can be obviatedhowever, by using a plurality of filament sections7 the combined lengthofwhich is relatively long.

One ofthe objects of the invention isto provide an electron dischargedevice having a relatively long cathode 'in which the mutual conductanceis a maximum for a given amplification constant, v

Another ob] ect is to provide a discharge del VVTtwice',A the cathodeof'which has ya large electron-emitting area and in which the averagedistance between the anode and cathode is relatively small.

Another object is to provide asingle radio tube which will performaplurality of functions heretofore requiring separate tubes.

Another object is to provide a radio tube of simple construction whichwill be eiiicient and reliable in operation and which will have a longlife. A

Other objects and advantages will hereinafter appear.

In accordance with this invention, the electron discharge device isconstructed with a plurality of sets of electrodes. E ach setmaycomprise a cathode, a surrounding grid or 1924. 4 serial no. 728,831;

control electrode-and an anode encirclingthe" v grid and cathode. -1'Ihe'cathode is preferably p in the form of'a linear lament and thegrid' and plate are, in the preferred form, c'ylin'dri- A cal andarranged relatively close to the iila-v ment and lto each other wherebythe distance between the fila-ment and plate is substantially const-ant'for each part of the plate-andA` relatively short.- By' using aplurality of' anodes and control electrodes, it is possible tofuseVseveral filament sectionsthe combined length of which is relativelylong, thus giving acomparatively large eiiective `electron-emitting yarea. Byusing a relatively long filamentga suitableelectron-emission-'may be .obtained at relatively lowtemperature,=thereby pro-k longing the life of the'device. 1

The corresponding electrodes of each'set,-

may be connectedin vparallel althoughif desired,.the filament sectionsmay be operated in series rand the'v grids provided with inde# pendentleads, whereby one set of electrodes vfor instance lmayv be used fordetection of radio signals and the otherset for amplilica tion thereof.w" Whilean'electron discharge device having but two sets'of electrodesis shown and described 'herein,`V itis obvious that' any: Vother numbermight equally Awell be provided.' I f In order that `this invention maybe more 'fullyunderstood,V reference" will be'.` had to theaccompanying` drawings in which,

I'Fig. l isfa perspective Vview'of a mount for a radio ,tubeembodyinggthis invention; -V

of the 'modi- "laY n 'so f of grids orcontrolielectrodes and jand pairof cathode sections V6 fand `7. The'anodes 2 4and 3 ar'epreferablycylindrical-inform and arranged concentrically withv respect to thecathode in order to obtain a minimum .average anodecathode spacing'.HrIhe anode Q vissupported by and joined to theanodefV-B in parallelrelation-by strap'sor webs 8which may be integral with theV anodes or*formed Y separately and weldedoil otherwise secured thereto. The anode 3is supported from the stem by the conducting support wire 9 to which itis secured by projections 10 formed on the outer side thereof and bentaround or welded to the support. The supporting wire 9 is sealed in thekpress of the stem 1 and may be joined to or form a continuation of theleading-in wire 12.

The grids or control electrodes 4 and 5 are arranged within the anode orplates 2 and 3 respectively, and are of similar shape. These controlelectrodes may be supported at the lower end by divergent arms 13 and 14of the supporting lead 15 sealed into the Vstem andV at the upper ends,they may be connected Yby. a bridging member 16 which may Vbe supportedfrom' the upper web 8 by a wire 17 insulated from the cross piece 16 bya glass bead 18 or other suitable means.

. The gridv supporting wire 15 is connected to or'forms a continuationof the leading-V in wire 24.v Y Y The filament sections Gand 7 passaxially through the grid and anode and are connected at their lowerendslto the leading-in wires 19'and 20 respectively. Their upperends arepreferably joined by a vconnecting bar or bridging member 2l',resiliently supported by ac-hook 22 carried at the upper end of asupporting wire 23, sealed into the stem press of theY device. Y Y Y Inthe modifications shown in Figs. 2 and 3, the plates 2 and 3 are formedfrom a single sheet of metal bent to the form of .a iigure 8,. rllheseplatesare supported at ktheir mid portion by a singleV centralsupporting` lead 25 welded or otherwise suitably secured capable ofservin thereto. In this embodiment of the invention, the upper end ofthe filament sections 6 and 7 are supported from the horizontal arm26.01? the supporting conductor 27.v Each of the grids 28and 29 aresupported by. independent conductors 30 andv 31 'joined to'or ormingvcontinuationsV of 'the leading-in wires 32 and 33. vThis formV of `tubeis particularly adaptedv for actual use, it being simultaneously as adetector and ampli erV or for both radioy and audio frequencyamplification, by suitably connectin xthe-V independent grids' in`independent circuits in the radio receiving appa,-

`ratus, as' disclosed, for example, in Eig; 2.

` modifications and variationswithout depart;

The arrangement of the electrodes otherwise is substantially the same asshowninAFig. 1.l

Obviously, this invention is not limited to the specificembodiments'shown and de,- scribed herein buty is susceptible of manying therefrom.

What is claimed is:

1.. In a vacuumrtube device, a member; of

sheet material off S-shapedV cross-sectiongprof Viding twoconnectedcylindricalportions and means whereby each; 'cylindricalpnrtipn0011.-, stitutes an anode, Y f

2. An electron-discharge device comprising a pair of cylindrical anodesforming an integral metallic structure electrically inter- A nected landsaidgrids beingelectrically sep'- arate. Y

3. In combination with an electron tube having an electrically unitarycathode, an electrically unitary anode and a plurality of electricallyindependent grids, means for impressing independent E. M. F.s on saidgrids.

4. VIn combinationwith an electrical system comprising a plurality ofcircuits, an electron tube having an anode comprisingl a unitarystructure, an electrically unitarycathode and a plurality of grids, andmeans for impressing'E. M. F.s derived from different members of saidplurality of circuits on different grids. Y i

5. In combination with a radio receiving system comprising circuits; ofdifferent frequencies and an electron tube having a unitary anode, -aunitary cathode andv separate grids, means for impressing vaA periodicE. M. Il. derived from; a circuit of oneofsaid frequencies onone gridand for impressing a periodic,` E. M. derived; from a, circuit ofanother of said frequencieson another grid.

6. An electrical-discharge device having a ns I

